`1)A=((a+sqrta)/(sqrta+1)+(a-4sqrta+4)/(sqrta-2)).(3/(sqrta-1))`
`đk:x>=0,x ne 1`
`A=((sqrta(sqrta+1))/(sqrta+1)+(sqrta-2)^2/(sqrta-2)).(3/(sqrta-1))`
`=(sqrta+sqrta-2).(3/(sqrta-1))`
`=(2sqrta-2).(3/(sqrta-1))`
`=2.(sqrta-1).(3/(sqrta-1))`
`=2.3`
`=6`